1 /* libs/android_runtime/android/graphics/PathMeasure.cpp 2 ** 3 ** Copyright 2007, The Android Open Source Project 4 ** 5 ** Licensed under the Apache License, Version 2.0 (the "License"); 6 ** you may not use this file except in compliance with the License. 7 ** You may obtain a copy of the License at 8 ** 9 ** http://www.apache.org/licenses/LICENSE-2.0 10 ** 11 ** Unless required by applicable law or agreed to in writing, software 12 ** distributed under the License is distributed on an "AS IS" BASIS, 13 ** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 14 ** See the License for the specific language governing permissions and 15 ** limitations under the License. 16 */ 17 18 #include "jni.h" 19 #include "GraphicsJNI.h" 20 #include <android_runtime/AndroidRuntime.h> 21 22 #include "SkPathMeasure.h" 23 24 /* We declare an explicit pair, so that we don't have to rely on the java 25 client to be sure not to edit the path while we have an active measure 26 object associated with it. 27 28 This costs us the copy of the path, for the sake of not allowing a bad 29 java client to randomly crash (since we can't detect the case where the 30 native path has been modified). 31 32 The C side does have this risk, but it chooses for speed over safety. If it 33 later changes this, and is internally safe from changes to the path, then 34 we can remove this explicit copy from our JNI code. 35 36 Note that we do not have a reference on the java side to the java path. 37 Were we to not need the native copy here, we would want to add a java 38 reference, so that the java path would not get GD'd while the measure object 39 was still alive. 40 */ 41 struct PathMeasurePair { 42 PathMeasurePair() {} 43 PathMeasurePair(const SkPath& path, bool forceClosed) 44 : fPath(path), fMeasure(fPath, forceClosed) {} 45 46 SkPath fPath; // copy of the user's path 47 SkPathMeasure fMeasure; // this guy points to fPath 48 }; 49 50 namespace android { 51 52 class SkPathMeasureGlue { 53 public: 54 55 static PathMeasurePair* create(JNIEnv* env, jobject clazz, const SkPath* path, jboolean forceClosed) { 56 return path ? new PathMeasurePair(*path, forceClosed) : new PathMeasurePair; 57 } 58 59 static void setPath(JNIEnv* env, jobject clazz, PathMeasurePair* pair, const SkPath* path, jboolean forceClosed) { 60 if (NULL == path) { 61 pair->fPath.reset(); 62 } else { 63 pair->fPath = *path; 64 } 65 pair->fMeasure.setPath(&pair->fPath, forceClosed); 66 } 67 68 static jfloat getLength(JNIEnv* env, jobject clazz, PathMeasurePair* pair) { 69 return SkScalarToFloat(pair->fMeasure.getLength()); 70 } 71 72 static void convertTwoElemFloatArray(JNIEnv* env, jfloatArray array, const SkScalar src[2]) { 73 AutoJavaFloatArray autoArray(env, array, 2); 74 jfloat* ptr = autoArray.ptr(); 75 ptr[0] = SkScalarToFloat(src[0]); 76 ptr[1] = SkScalarToFloat(src[1]); 77 } 78 79 static jboolean getPosTan(JNIEnv* env, jobject clazz, PathMeasurePair* pair, jfloat dist, jfloatArray pos, jfloatArray tan) { 80 SkScalar tmpPos[2], tmpTan[2]; 81 SkScalar* posPtr = pos ? tmpPos : NULL; 82 SkScalar* tanPtr = tan ? tmpTan : NULL; 83 84 if (!pair->fMeasure.getPosTan(SkFloatToScalar(dist), (SkPoint*)posPtr, (SkVector*)tanPtr)) { 85 return false; 86 } 87 88 if (pos) { 89 convertTwoElemFloatArray(env, pos, tmpPos); 90 } 91 if (tan) { 92 convertTwoElemFloatArray(env, tan, tmpTan); 93 } 94 return true; 95 } 96 97 static jboolean getMatrix(JNIEnv* env, jobject clazz, PathMeasurePair* pair, jfloat dist, 98 SkMatrix* matrix, int flags) { 99 return pair->fMeasure.getMatrix(SkFloatToScalar(dist), matrix, (SkPathMeasure::MatrixFlags)flags); 100 } 101 102 static jboolean getSegment(JNIEnv* env, jobject clazz, PathMeasurePair* pair, jfloat startF, 103 jfloat stopF, SkPath* dst, jboolean startWithMoveTo) { 104 return pair->fMeasure.getSegment(SkFloatToScalar(startF), SkFloatToScalar(stopF), dst, startWithMoveTo); 105 } 106 107 static jboolean isClosed(JNIEnv* env, jobject clazz, PathMeasurePair* pair) { 108 return pair->fMeasure.isClosed(); 109 } 110 111 static jboolean nextContour(JNIEnv* env, jobject clazz, PathMeasurePair* pair) { 112 return pair->fMeasure.nextContour(); 113 } 114 115 static void destroy(JNIEnv* env, jobject clazz, PathMeasurePair* pair) { 116 delete pair; 117 } 118 }; 119 120 static JNINativeMethod methods[] = { 121 {"native_create", "(IZ)I", (void*) SkPathMeasureGlue::create }, 122 {"native_setPath", "(IIZ)V", (void*) SkPathMeasureGlue::setPath }, 123 {"native_getLength", "(I)F", (void*) SkPathMeasureGlue::getLength }, 124 {"native_getPosTan", "(IF[F[F)Z", (void*) SkPathMeasureGlue::getPosTan }, 125 {"native_getMatrix", "(IFII)Z", (void*) SkPathMeasureGlue::getMatrix }, 126 {"native_getSegment", "(IFFIZ)Z", (void*) SkPathMeasureGlue::getSegment }, 127 {"native_isClosed", "(I)Z", (void*) SkPathMeasureGlue::isClosed }, 128 {"native_nextContour", "(I)Z", (void*) SkPathMeasureGlue::nextContour }, 129 {"native_destroy", "(I)V", (void*) SkPathMeasureGlue::destroy } 130 }; 131 132 int register_android_graphics_PathMeasure(JNIEnv* env) { 133 int result = AndroidRuntime::registerNativeMethods(env, "android/graphics/PathMeasure", methods, 134 sizeof(methods) / sizeof(methods[0])); 135 return result; 136 } 137 138 } 139